Tray unloader



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Sept. 27, 1932. H. B. MILLER TRAY UNLOADER Filed March 25, 1936 H. B. MALLER TRAY UNLOADER v Fileduarcn z5., 195o gwn 279 1932.

2 Sheets-Sheet 2 INVIENTOR:A

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Patented Sept. 27, 1932 UNITED STATES HERMAN IB. MILLER, OF SAN FRANCISCO, CJAIIIIEORNIA TRAY UNLOADER Application led March 25,1930. Serial No. 438,737.

My invention relates to tray unloaders and i the object of my invention is to providea simple and efficient machine for quickly and easily unloading a plurality of articles, as cans of canned goods, from a tray.

In the handling of canned goods in a cannery it is customary to put the cans in metal trays preparatory to placing them in the cooking ovens or retorts. After these trays,

loaded with cans, have been removed from the cooking retorts, they are placed on platforms, one tray upon another, and are transported, usually on trucks, to locations where they are stacked up and allowed to cool.

l,Vhen lithographed cans are used, the cans are ready to be packed in the boxes as soon as they have cooled but when non-lithographed cans are used they must be put through can labeling machines and have labels placed thereon before they can be boxed. In the case of the lithographed cans, it has heretofore been common practice to have the cans removed from the trays by hand and placed in boxes at the locations of the stacks where they are cooled, and to then have the filled boxes and the empty trays picked up. In the case of non-lithographed cans, it has been common practice to transport the cans, in the trays, to labeling ma- 3o chines then to remove the cans, by hand,

from the trays and place them in the labeling machines. In both of these instances the cans must be picked out of the trays by hand thus consuming muchtime and labor and often holding up other operations in the cannery. Where the lithographed cans are taken out of the trays and placed in the boxes by hand at the location of the cooling stacks additional floor space is also required.

My present invention does away with the hand labor of removing the cans from the trays, and, in the case of lithographed cans, makes it advantageous to use box filling for loading the cans into boxes where heretofore .5 this work has been done by hand.

It is a primary object of this invention to provide a tray unloader which will quickly and easily and with a small expenditure of labor, unload cans or similar goods from trays and deposit the same on an endless movlng conveyor.

Another object of this invention is to provide a tray unloader embodying means for inverting the tray with the cans therein, whereby the tray may be quickly and easily lifted off of the cans and said cans left standing in an inverted position on an inclined movable platform from which the said cans are fed by gravity onto a conveyor.

Other objects are to provide a tray unloader embodying a frame having two platforms pivoted thereon at adjacent edges and arranged to swing between substantially horizontal and vertical positions, whereby a tray loaded with cans may be placed right side 65 up on one of said platforms while the platform is in a substantially horizontal position the-n raised to a substantially vertical position and transferred to the other platform, which has previously been raised into a sub- 'stantially vertical position, and then lowered by said other platform in such a manner that the trays are inverted and may be easily removed, while the cans are'left standing on said last named platform, which is inclined at sufficient angleV so that the cans will slide by gravity onto a conveyor by which they may be carried to boxing or labeling machines. Another object is to provide compressed fluid operating means, preferably pneumatic, for raising and lowering said two platforms, and to provide automatic shut olf devices for said compressed fluid operating means.

Other objects are to provide means for preventing the trays from falling away from the platforms when said platforms are in a substantially vertical position, and to provide means for adjusting the distance between the receiving and the discharge platforms to adapt the machine for handling cans of different height.

Other and more specific objects will be apparent from the following description taken in connection with the accompanying drawings, throughout which drawings like reference numerals indicate like parts:

Figure 1 is a plan view looking down onto a tray unloading machine, constructed in accordance with my invention, showing both swinging platforms lowered;

Fig. 2 is a side elevation of the same showing one of the platforms raised and the other platform lowered and supporting a tray of cans ready to be raised for the purpose of transferring the tray and the cans in inverted position to the other platform, said tray and cans being shown by dotted lines;

Fig. 3 is a longitudinal section substantially on broken line 3-3 of Fig. V1, showing, by full lines, both platforms in a raised position, and, by dotted lines, the discharge platform in a lowered position;

Fig. 4 is a fragmentary elevation on a larger scale of the automatic valve shut olf means;

Fig. 5 is a detached sectional view of one of the four way valves, showing the spring closing means for the same;

Fig. 6 is a detached view in cross section of a conveyor belt by which the cans are removed from the unloader and a guard for preventing the cans from tipping over on said belt;

Fig. 7 is a plan view of a tray which this machine is designed to handle; and

Fig. 8 is a sectional View of the tray on broken line 8 8 of Fig. 7.

Referring to the drawings, 8 designates the side bars, 9 and 10 the transverse end bars and 11 the legs of a frame upon which my unloading devices are mounted. The unloading devices comprise a receiving platform 12 and a discharge platform 13 which are secured by bracket lugs 14 to two shafts 15 and 16 which extend crosswise of the frame substantially mid-way between the two ends and are mounted for oscillatory movement in bearing brackets 17 which are secured to the side bars 8. The receiving platform 12 rests on the frame. bar 9 and is supported in a substantially horizontal position when lowered. The discharge platform 13 rests on the cross bar 10 at the opposite end of the frame, when it is lowered, and is sufficiently inclined to cause the cans to discharge therefrom, by gravity, onto an inclined conveyor 18, which is preferably an endless belt. Narrow side members 19 may be provided on the edges of the discharge platform 13 to prevent the cans from being crowded sidewise off of said platform.

The receiving platform 12 is providedon the edge adjacent the pivot shaft 15, with stop members 21 which extend outwardly from said platform at slightly less than right larly provided with upwardly extending stop l members 22 which are offset relative to the members 21 so that the members 21 and 22 will not interfere with each other when both platforms 12 and 13 are raised.

rlhe receiving platform 12 is connected by lugs 23 with the piston rod 24 of a fluid pressure cylinder 25, the bottom end of which is connected by combined pivot and bracket means 26 with a base support 27 of the frame.

A piston 28, shown by dotted lines in Fig. 3, f

is secured to the end of the piston rod 24 within the cylinder 25. The discharge platform 13 is similarly connected by lugs 29 with a piston rod 30 having, on its bottom end, a piston 31 shown by dotted lines in Fig.

3, which is disposed within a cylinder 32. The cylinder 32 is connected by pivot means with the base frame support 27.

The fluid pressure cylinder 32 is connected by conduits 34 and 35 with a four way valve 36. The valve36 has a discharge poit 37 and is connected with a source of supply conduit 38 through which fluid under pressure, preferably compressed air, may be admitted. The cylinder 25 is similarly connected by conduits 39 and 40 with a four way valve 41 which has an intake conduit 42 and a discharge port 43. Valve levers or handles 44 and 45 are pro vid-ed on the respective valves 36 and 41 for operating the same. are provided on t-lie rear ends of the handles 44 and 45 for urging the valves into a closed or inoperative position.

To insure closing of the four way valves when the receiving and discharge platforms I 12 and 13 reach a vertical position I provide two sets of automatic valve shut off devices which are operated by the movement of said Vplatforms as they approach the vertical. These shut off devices are in duplicate, one Tf in connection with each platform, and each set embodies a disc 48 adjustably secured to the shaft 15 or 16. Each disc 48 is connected by a crank pin 49 with a substantially horizontal link 50 and said link 50 is connected by an adjustable slot and pin connection 51 with the upper end of an upright lever 52. The lever 52 is fulcrumed on a pivot 53 and the lower end of said lever is adapted to engage with the adjacent valve V Springs 46, see Fig. o, Y- Y the valve is closed. The position of the latform at which said valve will be fully c osed may be varied by adjusting the position of the discs 48 on the shafts 15 and 16.

Adjustment to allow cans of different height to be unloaded in this machine is afforded by making the bearings 17 of the shaft 15 horizontally adjustable lengthwise of the fram-e members 8. This is done by providing lugs 54 on said bearings 17, which lugs are slidable in slots 55 in the frame members 8 and are adjustably supported by screws 56. To compensate for the adjustment above described it is desirable to make the lower end of the cylinder 25 longitudinally adjustable by connecting the pivot bracket- 26 with an adjusting screw 57. f

In the operation of this tray unloader, the trays 58, Figs. 7 and 8, filled with cans, as indicated by broken lines 59 in Figs. 2 and 3, are placed on the lowered receiving platform 12, usually by means of a power hoist, not shown, it being understood that each tray contains from one hundred to two hundred cans, depending on the sise of the individual cans, and that the loaded trays are relatively heavy. The valve levers 44@ and 45 are then manipulated by the operator to open the valves 36 and i-O and bring, first the discharge platform 13 and then the receiving platform 12, with its tray of cans, up to the vertical position as shown in F ig. 3. As the receiving platform 12 approaches the vertical position the tray of cans will be prevented from tipping forwardly by the lugs or lingers 21, which are inclined at less than a right angle from the plane of the tray, and which support the edge of the tray. Due to the fact that the discharge platform 13 is already in a vertical position at the time the receiving platform is raised the lugs or lingers 22 on said discharge platform 13 will be positioned underneath the edge of the tray and, when the valve 36 is opened and said discharge platform 13 is swung to the left in lowering` the same the fingers 22 will lift the tray ofthe fingers 21 and away from the receiving platform 12 and will lower the saine to the position shown by dotted lines in Fig. 3, with the cans resting on the discharge platform 13 and the tray resting on top of the cans where it may easily and quickly be lifted off.

lWhen lowered, the discharge platform 13 rests on the cross bar 10 of the frame and is sufficiently inclined to cause the cans to feed, by gravity, off onto the belt 13 which moves, preferably crosswise, past the end of the machine. The automatic shut off devices engage the valve handles A4 and l5 and bring the platforms 12 and 13 easily but surely to a complete stop as said platforms reach the vertical position, and said stop means operative in this manner regardless of whether or not the operator, is grasping the valve handles. The easy and gradual stopping of the receiving platform 12 is especially desirable because it prevents any possibility of throwing the cans toward the raised platform 13 which might occur if movement of the platform 12 was checked too quickly.

The belt 13 may lead to boxing machines in the event lithographed cans are being handled or it may lead to labeling machines when non-lithographed cans are being handled, and said belt has a guard 60 extending over the top of the same to prevent tipping over of the cans. This guard is adjustably supported by brackets 61 and may be raised and lowered to accommodate cans of different heighth. It is usually set to afford about one-fourth inch clearance above the cans. TvVith either lithographed or non-lithographed cans, this machine saves the labor of removing the cans from the trays by hand and when the lithographed cans are used it makes it possible to profitably employ boX- ing machines for boxing the cans, whereas, with the old method of removingthe cans from the trays by hand no advantage is gained by the use of boxing machines.

Obviously, changes may be made in the form, dimensions, and arrangement of the parts of my invention, without departing from the principle thereof, the above setting forth only a preferred form of embodiment.

I claim:

1. A tray unloader of the class described, embodying a frame; a receiving platform at one end of said frame; a discharge platform at the other end of said frame, the edges of said two platforms extending across the medial portion of said frame; pivot means connecting each of said adjacent edges with said frame; upwardly projecting relatively offset fingers on the adjacent edges of both of said platforms, the fingers on said receiving platform supportiner a tray when said receiving platform is in the upright position and the fingers on said discharge platform being positioned underneath the edge of said tray when said discharge platform is first raised and said receiving platform is later raised parallel to said discharge platform whereby said discharge platform lingers will pick up a tray from said receiving platform and lower said tray in inverted position when said discharge platform is lowered; means on said frame for limiting the downward movement of discharge platform to an angle inclined downwardly relative to the horizontal to allow a gravity discharge of objects therefrom; fluid pressure means for raising and lowerii'ig both of said platforms; valves controlling' the operation of said fluid pressure means; and devices connected with the pivots of said platforms for closing said valves automatically when said platforms reach a vertical position.

2. A tray unloader of the class described. embodying a frame; two parallel shafts ro? 1 other shaft; fluid pressure means connected with the platforms for moving said platforms between substantially vertical and substantially horizontal posit-ions; valves controlling the flow of fluid to said fluid pressure means; handles on said valves allowing manual operation of the same; crank means on the ends of said shafts; links connected with said crank means; and levers connected with said links and engaging said handles for automatically closing said valves when said platforms reach a vertical position.

3. A tray unloader of the class described, embodying a frame; two parallel shafts rotatably mounted and extending crosswise of said frame in slightly spaced apart relation; a receiving platform secured to one of said shafts, a` discharge platform secured to the other shaft; means relatively adjusting said two shafts toward and away from each other varying the clearance between said platforms when said platforms are vertical; means for raising and lowering said platforms; and adj usting means moving said raising and lowering means relative to each other.

4. A tray unloader of the class described, embodying a frame; two parallel shafts rotatably mounted and extending crosswise of said frame in slightly spaced apart relation; a receiving platform secured to one of said shafts, a discharge platformsecured to the other shaft; means for adjusting one of said shafts toward and away from the other shaft fluid pressure cylinders pivotally mounted below said platforms; pistons in said cylinders; rods connecting said pistons with said platforms; means for adjusting the pivotal mounting of the cylinder which is connected with the adjustable platform; and valve means for controlling the flow and release of fluid for said cylinders.

5. In an unloader of the class described, embodying a frame; two platforms; pivot means securing said platforms to said frame whereby said platforms are pivotally mounted on said frame for swinging movement toward and away from each other between a substantially vertical parallel transfer position, and a horizontal position; interlocking means on the lower edges of said platforms for supporting objects and for transferring said object from one platform to the other; power operated means for raising and lowering said platforms; and automatic safety stop means connected to said pivot means whereby the upward movement of said platforms is limited.

6. A tray unloader of the class described, embodying a frame; two platforms; pivotal means securing said platforms to said frame r whereby said frame is pivotally mounted on and operated by said pivot means whereby "A said valves may be gradually closed as the platforms approach a vertical position.

In witness whereof, I hereunto subscribe my name this 28th day of February; 1930. HERMAN B. MILLER. 

